As a paper sheet stacking apparatus for stacking paper sheets, such as banknotes, checks, coupons or other valuable media, on one another, an apparatus disclosed in JP2002-193517A is known. In the paper sheet stacking apparatus disclosed in JP2002-193517A, various kinds of paper sheets are collectively received in a paper sheet supply unit, the paper sheets are taken into a housing one by one from the paper sheet supply unit and transported along a transport path, and denominations and/or fitness of the paper sheets are judged by a judging unit. Based on the judgment result, the paper sheets that have been judged by the judging unit are divided into fit notes and reject notes and so on, and are stacked on a stacking unit.
In the paper sheet stacking apparatus disclosed in JP2002-193517A, the stacking unit is provided with a rotatable stacking wheel. A plurality of vanes are arranged at an interval equal to each other, on an outer circumferential surface of a cylindrical body part of the stacking wheel. During the rotation of the stacking wheel, a paper sheet is sent into between a pair of vanes, and the paper sheet sandwiched between the pair of vanes is transported up to the stacking unit along a rotational direction of the stacking wheel. Due to the provision of such a rotatable stacking wheel on the stacking unit, paper sheets sandwiched between the pairs of the vanes of the stacking wheel can be stacked on one another on the stacking unit.
FIG. 14 shows a structure of a conventional paper sheet stacking apparatus in which a stacking unit is provided with a stacking wheel. The paper sheet stacking apparatus shown in FIG. 14 includes a feeding unit 52 configured to feed paper sheets one by one from an outside of the paper sheet stacking apparatus into an inside thereof, a rotatable stacking wheel 54 to which the paper sheets fed by the feeding unit 52 are sent, and a stacking stage 56 on which the paper sheets sent from the rotatable stacking wheel 54 are stacked on one another. A plurality of vanes 54b are arranged at an interval equal to each other, on an outer circumferential surface of a cylindrical body part 54a of the stacking wheel 54. The stacking wheel 54 can be rotated in the clockwise direction in FIG. 14 (direction shown by the arrow in FIG. 14) about a shaft 54c. During the rotation of the stacking wheel 54, a paper sheet P (indicated by the broken line in FIG. 14) is sent into between a pair of vanes 54b, and the paper sheet P sandwiched between the pairs of vanes 54b is transported up to the stacking stage 56 along the rotational direction of the stacking wheel 54.